;;; FG42 --- The mighty editor for the emacsians -*- lexical-binding: t; -*-
;;
;; Copyright (c) 2010-2023 Sameer Rahmani <lxsameer@gnu.org>
;;
;; Author: Sameer Rahmani <lxsameer@gnu.org>
;; URL: https://devheroes.codes/FG42/FG42
;; Version: 3.0.0
;;
;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
;;
;;; Commentary:
;; `System' is just a state monad which holds the state of the editor.
;; Each system has to have a `start' function to start the setup process.
;;
;;; Code:
(require 'seq)
(require 'fg42/utils)

(fpkg/require 's)

(defmacro ->commands (&rest body)
  "Return a list of shell commands in the BODY.

Each element has to be list like `(cd \"..\")' the command is static but
the arguments get evaluated."
  `(quote
    ,(mapcar
      (lambda (x)
        (when (not (listp x))
          (error "Expect a list.  Got %s" x))
        (let ((command (car x))
              (args (cdr x)))
          (cond
           ((string= command "and") (s-join " && " (eval `(->commands ,@args))))
           ((string= command "or") (s-join " || " (eval `(->commands ,@args))))
           (t (format "%s %s" command (mapconcat #'eval args " "))))))
      body)))


(defun shell<- (commands &rest opts)
  "Run the give list of COMMANDS via ssh on HOST with the given OPTS.

OPTS:
- `:shell' The shell to run the commands with.  (default /bin/bash)
- `:buffer' The buffer name to use.  (default '*ssh[SHELL]*')
- `:erase?' Whether or not erase the buffer.  (default t)"
  (let* ((sh (or (plist-get opts :shell) "/bin/bash"))
         (buffer (or (plist-get opts :buffer) (format "*shell[%s]*" sh)))
         (erase? (or (plist-get opts :erase-buffer?) t))
         (cmds (format "'%s'" (mapconcat #'identity commands ";")))
         (output-buffer (get-buffer-create buffer)))

    (when erase?
      (with-current-buffer output-buffer
        (setq buffer-read-only nil)
        (erase-buffer)))
    (let ((p (start-process-shell-command
              "shell<-"
              (buffer-name output-buffer)
              (format "%s -c %s"
                      sh
                      cmds))))
      (set-process-sentinel p
                            (lambda (_ event)
                              (when (string= event "finished\n")
                                (message "Commands finished.")
                                ;;(kill-process process)
                                ))))))


(defun ssh<- (host commands &rest opts)
  "Run the give list of COMMANDS via ssh on HOST with the given OPTS.

OPTS:
- `:shell' The shell to run the commands with.  (default /bin/bash)
- `:buffer' The buffer name to use.  (default '*ssh[HOST]*')
- `:erase?' Whether or not erase the buffer.  (default t)"
  (let* ((sh (or (plist-get opts :shell) "/bin/bash"))
         (buffer (or (plist-get opts :buffer) (format "*ssh[%s]*" host)))
         (erase? (or (plist-get opts :erase-buffer?) t))
         (cmds (format "'%s'" (mapconcat #'identity commands ";")))
         (output-buffer (get-buffer-create buffer)))

    (when erase?
      (with-current-buffer output-buffer
        (setq buffer-read-only nil)
        (erase-buffer)))

    (let ((p (start-process-shell-command
              (format "ssh-to-%s" host)
              (buffer-name output-buffer)
              (format "ssh -t %s %s -c %s"
                      host
                      sh
                      cmds))))
      (set-process-sentinel p
                            (lambda (_ event)
                              (when (string= event "finished\n")
                                (message "Commands finished. Closing SSH connection.")
                                ;;(kill-process process)
                                ))))))


(provide 'fg42/shell)
;;; ssh.el ends here